1. Technical Field
The present invention relates to a retainer ring which is installed to a polishing head of a chemical-mechanical polishing device for processing semiconductor wafers, and more particularly, to a retainer ring of a chemical-mechanical polishing device which can prevent itself from being twisted and improve defective proportion and equipment operating rate occurred when polishing semiconductor wafers by embedding a metal member inside.
2. Background Art
Recently, surface ununiformity of a semiconductor device has been increased in accordance with the tendencies of high density, fineness and variety of wiring structures of the semiconductor device.
Thus, various devices have been developed to increase the degree of flatness of the semiconductor device's surface. A chemical mechanical polishing device, which makes the surface of the semiconductor device flat by performing a chemical polishing work and a mechanical polishing work at the same time, is widely used.
Such a conventional chemical mechanical polishing device gets a semiconductor wafer 30 absorbed to the bottom of a polishing head retaining the semiconductor wafer 30, wraps the semiconductor wafer 30 with a retainer ring so that the semiconductor wafer 30 is not relieved of the bottom of the polishing head during polishing the semiconductor wafer 30, and polishes the semiconductor wafer 30 with a slurry provided between the semiconductor wafer 30 and the polishing pad while the semiconductor wafer 30, which is retained in the polishing head, is pressed toward the polishing pad at a predetermined pressure.
At this time, the semiconductor wafer 30 is polished by the slurry and the rotation movement of the polishing pad 20 chemically and mechanically at the same time.
FIG. 7 shows a sectional view illustrating a retainer ring of a conventional chemical mechanical polishing device.
The retainer ring 720 is comprised of a first member 722, which is contacted to the polishing pad 20, and a second member 724, which is connected to a carrier of the polishing head.
The first member 722 is made of resin material as like engineering plastic whereas the second member 724 is made of metal material as like stainless steel.
Further, the first member 722 and the second member 724 are bonded together firmly by bonding using adhesives.
Such the retainer ring 720 can prevent its deformity and damages of the polishing pad 20 because the degree of flatness of the bottom side of the first member, which is connected to the polishing pad 20, is maintained by the second member made of metal material.
However, such the conventional retainer ring of the chemical-mechanical polishing device has a problem that scratches of the semiconductor wafer can occur because particles can be generated by corrosion of the slurry due to the bonding.
Further, uniformity within the semiconductor wafer is not enough and, accordingly, reduction of product yield can be caused because space contacting pressure between the polishing pad 20 and the semiconductor wafer cannot to be maintained evenly around the circumference of the semiconductor wafer by deformation due to the twist effect of the retainer ring
Still further, polishing speed at the selected area of the semiconductor wafer is not constant and, accordingly, defective proportion is relatively higher because the flow of the slurry is not smooth enough in the conventional retainer ring.
Technical Problem
An object of the present invention is to provide a retainer ring of a chemical Mechanical polishing device capable of preventing it self from being twisted even without using bonding connection, preventing particles from being generated in accordance with the corrosion of the slurry due to the bonding of an engineering plastic, smoothing the flow of the slurry of polishing material, and reducing production cost by embedding a metal member inside itself.
Another object of the present invention is to provide a retainer ring for a chemical mechanical polishing device capable of easing attaching and/or detaching and preventing from being loosened by making the retainer ring with a upper portion and a lower portion, and connecting them by a plurality of bolts made of resin material.